usbtmc 3-1:0.0: unknown status received: -71
usbtmc 4-1:0.0: unknown status received: -71
usbtmc 3-1:0.0: unknown status received: -71
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 1, t=10502 jiffies, g=206173, q=174)
rcu: All QSes seen, last rcu_preempt kthread activity 10488 (4295081878-4295071390), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10488 jiffies! g206173 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:28872 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4322 [inline]
 __schedule+0x911/0x21b0 kernel/sched/core.c:5073
 schedule+0xcf/0x270 kernel/sched/core.c:5152
 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1892
 rcu_gp_fqs_loop kernel/rcu/tree.c:2005 [inline]
 rcu_gp_kthread+0xd07/0x2250 kernel/rcu/tree.c:2178
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 5419 Comm: kworker/1:7 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_dev_trap_report_work
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_check_gp_kthread_starvation+0x1c7/0x1e4 kernel/rcu/tree_stall.h:478
 print_other_cpu_stall kernel/rcu/tree_stall.h:582 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:706 [inline]
 rcu_pending kernel/rcu/tree.c:3830 [inline]
 rcu_sched_clock_irq.cold+0x9a3/0x11dd kernel/rcu/tree.c:2650
 update_process_times+0x16d/0x200 kernel/time/timer.c:1796
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1369
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:191
Code: 74 24 10 e8 ca f8 53 f8 48 89 ef e8 02 af 54 f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 <e8> e3 7c 48 f8 65 8b 05 8c 47 fc 76 85 c0 74 0a 5b 5d c3 e8 50 38
RSP: 0018:ffffc90000dc0b28 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000200 RCX: 1ffffffff1f5f91a
RDX: 0000000000000000 RSI: 0000000000000103 RDI: 0000000000000001
RBP: ffff888144550000 R08: 0000000000000001 R09: ffffffff8fa9a9a7
R10: 0000000000000001 R11: ffffc9000fc96000 R12: ffff888144581440
R13: ffff888025423800 R14: dffffc0000000000 R15: ffff888014261a00
 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline]
 dummy_timer+0x12f1/0x32a0 drivers/usb/gadget/udc/dummy_hcd.c:1985
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1431
 expire_timers kernel/time/timer.c:1476 [inline]
 __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1745
 __run_timers kernel/time/timer.c:1726 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1758
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345
 do_softirq.part.0+0xd9/0x130 kernel/softirq.c:248
 </IRQ>
 do_softirq kernel/softirq.c:240 [inline]
 __local_bh_enable_ip+0x102/0x120 kernel/softirq.c:198
 spin_unlock_bh include/linux/spinlock.h:399 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:585 [inline]
 nsim_dev_trap_report_work+0x867/0xbd0 drivers/net/netdevsim/dev.c:611
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

================================
WARNING: inconsistent lock state
5.12.0-rc8-syzkaller #0 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
kworker/1:7/5419 [HC0[0]:SC1[1]:HE0:SE0] takes:
ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:541 [inline]
ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:706 [inline]
ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3830 [inline]
ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq.cold+0x2b9/0x11dd kernel/rcu/tree.c:2650
{IN-HARDIRQ-W} state was registered at:
  lock_acquire kernel/locking/lockdep.c:5511 [inline]
  lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5476
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159
  rcu_report_exp_cpu_mult+0x73/0x3a0 kernel/rcu/tree_exp.h:237
  flush_smp_call_function_queue+0x34b/0x640 kernel/smp.c:426
  __sysvec_call_function_single+0x95/0x3d0 arch/x86/kernel/smp.c:248
  sysvec_call_function_single+0x8e/0xc0 arch/x86/kernel/smp.c:243
  asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:640
  lock_acquire+0x1ef/0x740 kernel/locking/lockdep.c:5479
  __fs_reclaim_acquire mm/page_alloc.c:4332 [inline]
  fs_reclaim_acquire+0x117/0x150 mm/page_alloc.c:4346
  might_alloc include/linux/sched/mm.h:194 [inline]
  slab_pre_alloc_hook mm/slab.h:497 [inline]
  slab_alloc_node mm/slub.c:2826 [inline]
  slab_alloc mm/slub.c:2915 [inline]
  kmem_cache_alloc+0x3e/0x370 mm/slub.c:2920
  getname_kernel+0x4e/0x370 fs/namei.c:218
  kernel_execve+0x24/0x460 fs/exec.c:1936
  call_usermodehelper_exec_async+0x2de/0x580 kernel/umh.c:110
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
irq event stamp: 1091837
hardirqs last  enabled at (1091836): [<ffffffff8905a840>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
hardirqs last  enabled at (1091836): [<ffffffff8905a840>] _raw_spin_unlock_irqrestore+0x50/0x70 kernel/locking/spinlock.c:191
hardirqs last disabled at (1091837): [<ffffffff890333cb>] sysvec_apic_timer_interrupt+0xb/0xc0 arch/x86/kernel/apic/apic.c:1100
softirqs last  enabled at (994534): [<ffffffff852f71a7>] spin_unlock_bh include/linux/spinlock.h:399 [inline]
softirqs last  enabled at (994534): [<ffffffff852f71a7>] nsim_dev_trap_report drivers/net/netdevsim/dev.c:585 [inline]
softirqs last  enabled at (994534): [<ffffffff852f71a7>] nsim_dev_trap_report_work+0x867/0xbd0 drivers/net/netdevsim/dev.c:611
softirqs last disabled at (994535): [<ffffffff81451a99>] do_softirq.part.0+0xd9/0x130 kernel/softirq.c:248

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rcu_node_0);
  <Interrupt>
    lock(rcu_node_0);

 *** DEADLOCK ***

6 locks held by kworker/1:7/5419:
 #0: ffff888010464d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888010464d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff888010464d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff888010464d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff888010464d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff888010464d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x871/0x1600 kernel/workqueue.c:2246
 #1: ffffc90017707da8 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2250
 #2: ffff88807189c390 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x5d/0xbd0 drivers/net/netdevsim/dev.c:606
 #3: ffff8880133050d8 (&nsim_trap_data->trap_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
 #3: ffff8880133050d8 (&nsim_trap_data->trap_lock){+.+.}-{2:2}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:556 [inline]
 #3: ffff8880133050d8 (&nsim_trap_data->trap_lock){+.+.}-{2:2}, at: nsim_dev_trap_report_work+0x1c7/0xbd0 drivers/net/netdevsim/dev.c:611
 #4: ffffc90000dc0d90 ((&dum_hcd->timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:35 [inline]
 #4: ffffc90000dc0d90 ((&dum_hcd->timer)){+.-.}-{0:0}, at: call_timer_fn+0xd5/0x6b0 kernel/time/timer.c:1421
 #5: ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:541 [inline]
 #5: ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:706 [inline]
 #5: ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3830 [inline]
 #5: ffffffff8bf7c918 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq.cold+0x2b9/0x11dd kernel/rcu/tree.c:2650

stack backtrace:
CPU: 1 PID: 5419 Comm: kworker/1:7 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_dev_trap_report_work
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 print_usage_bug kernel/locking/lockdep.c:202 [inline]
 valid_state kernel/locking/lockdep.c:3819 [inline]
 mark_lock_irq kernel/locking/lockdep.c:4022 [inline]
 mark_lock.cold+0x61/0x8e kernel/locking/lockdep.c:4479
 mark_held_locks+0x9f/0xe0 kernel/locking/lockdep.c:4080
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4098 [inline]
 lockdep_hardirqs_on_prepare kernel/locking/lockdep.c:4166 [inline]
 lockdep_hardirqs_on_prepare+0x135/0x400 kernel/locking/lockdep.c:4118
 trace_hardirqs_on+0x5b/0x1c0 kernel/trace/trace_preemptirq.c:49
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:191
Code: 74 24 10 e8 ca f8 53 f8 48 89 ef e8 02 af 54 f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 <e8> e3 7c 48 f8 65 8b 05 8c 47 fc 76 85 c0 74 0a 5b 5d c3 e8 50 38
RSP: 0018:ffffc90000dc0b28 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000200 RCX: 1ffffffff1f5f91a
RDX: 0000000000000000 RSI: 0000000000000103 RDI: 0000000000000001
RBP: ffff888144550000 R08: 0000000000000001 R09: ffffffff8fa9a9a7
R10: 0000000000000001 R11: ffffc9000fc96000 R12: ffff888144581440
R13: ffff888025423800 R14: dffffc0000000000 R15: ffff888014261a00
 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline]
 dummy_timer+0x12f1/0x32a0 drivers/usb/gadget/udc/dummy_hcd.c:1985
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1431
 expire_timers kernel/time/timer.c:1476 [inline]
 __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1745
 __run_timers kernel/time/timer.c:1726 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1758
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345
 do_softirq.part.0+0xd9/0x130 kernel/softirq.c:248
 </IRQ>
 do_softirq kernel/softirq.c:240 [inline]
 __local_bh_enable_ip+0x102/0x120 kernel/softirq.c:198
 spin_unlock_bh include/linux/spinlock.h:399 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:585 [inline]
 nsim_dev_trap_report_work+0x867/0xbd0 drivers/net/netdevsim/dev.c:611
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
------------[ cut here ]------------
timer: dummy_timer+0x0/0x32a0 include/linux/list.h:112 preempt leak: 00000102 -> 00000103
WARNING: CPU: 1 PID: 5419 at kernel/time/timer.c:1437 call_timer_fn+0x5d8/0x6b0 kernel/time/timer.c:1437
Modules linked in:
CPU: 1 PID: 5419 Comm: kworker/1:7 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:call_timer_fn+0x5d8/0x6b0 kernel/time/timer.c:1437
Code: e8 bd 86 10 00 89 da 4c 89 f6 48 c7 c7 20 75 6d 89 65 8b 0d ea 84 9e 7e 81 e1 ff ff ff 7f c6 05 97 85 4d 0c 01 e8 a1 ed 5e 07 <0f> 0b e9 80 fc ff ff e8 8c 86 10 00 0f 0b e9 fb fd ff ff e8 80 86
RSP: 0018:ffffc90000dc0d58 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000102 RCX: 0000000000000000
RDX: ffff888014ae9c40 RSI: ffffffff815c4d25 RDI: fffff520001b819d
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815bdabe R11: 0000000000000000 R12: 0000000000000000
R13: 1ffff920001b81ac R14: ffffffff8587b740 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c02469f000 CR3: 0000000020964000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 expire_timers kernel/time/timer.c:1476 [inline]
 __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1745
 __run_timers kernel/time/timer.c:1726 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1758
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345
 do_softirq.part.0+0xd9/0x130 kernel/softirq.c:248
 </IRQ>
 do_softirq kernel/softirq.c:240 [inline]
 __local_bh_enable_ip+0x102/0x120 kernel/softirq.c:198
 spin_unlock_bh include/linux/spinlock.h:399 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:585 [inline]
 nsim_dev_trap_report_work+0x867/0xbd0 drivers/net/netdevsim/dev.c:611
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294